Press for molding granular powders



Oct. 16, 1928. 1,687,995

R. L. SEABURY PRESS FOR MOLDING GRANULAR POWDERS Filed July 1926 2 SheetsSheet l Z1 9.1 [My 0) ksglnumlwz I 6% Z M L227. 1 8% mfg-6,

Oct. 16, 1928.

R. L. SEABURY PRESS FOR MOLDING GRANULAR POWDERS Filed July 8, 1926 2 Sheets-Sheet 2 gram-"loo attoruurb Fatented Oct. '16, 1928.

. UNITED STATES BALI-H L. SEABUBY, OF TOLEDO, OHIO.

PRESS FOB MOLDING Application filed July 8,

This invention relates to presses, but more particularly to presses for compressing or compacting granular powders into a rm, hard and compact mass.

Ordinarily presses of the above type are mechanically operated from a crank shaft, and although thesiae of the article which it is desired to produce largely governs the pressure required, it has been found that generally twent tons per square inch is suflicient. It will e apparent that tremendous power must be developed to exert such a pressure.

'and should a greater volume of material be placed in the mold, the machine will stall or,

16 as frequently happens, when the machine is very powerful, the mold becomes broken. It is further observe a maller quantity of material in the mold, th article formed is less dense while, on the an oth r hand, if a larger quantity of the matei l is supplied is more dense. Thus, there is lack of uniiormity in the articles produced.

Objects of this invention are to overcome the above difliculties; to provide a machine for compressing powdered material by which a definite predetermined pressure is elfected irrespective of the distance the pressure member travels; and to provide such machine which holds the pressure member in advanced posit-ion momentarily before commencing its retracting movement. Other ob ects and advantages will hereinafter appear;

Species of which this invention is a genus are shown in the accompanying draw ngs, m

which:

Figure 1 is a side elevation of a press embodying the invention; Fig. 2 is a section on the line 2-2 of Fig. 1; Fig. 3 is a view simllar to Fig. 1 with the press turned at right angles and with the connecting rod and slide in section; and Fig. 4 is a side elevation of an alternate form of the machine.

- The illustrated embodiment of the inven- 5 tion comprises a press havm a base 1 on which is mounted a machine rame 2, on the ripper portion of which is located a driven wheel 3 having a crank pin 4. Any suitable source of power may be provided for driving the wheel 3. Reciprocated by the crank pin 4 is a slide 5, which travels in a slotted guide 6 in a connecting rod 7 The lower end portion of the connecting rod 7 is pivotally connected to a cross-head 8, which is vertically reciprocable in guides 9. Carried by the lower end portion of the crosshead 8 is a that in the event there is to the mold, the article formed ennnonnn rownsns.

1926. Serial No. 121,112.

plunger or pressure member 10, which is adapted to enter a mold 1.1 in which powdered granular material may be placed. A lower punch 12.is reciprocable in the mold 11 and th1s member may function to eject the mass from the mold 11 after being compacted. Any suitable mechanism may be employed for actuating an arm 13 for imparting ejecting movement to the punch member 12.

The slide 5 is connected by bolts 14 to a yoke 15, which is connected by means of rods 16 to yoke 17. The yoke 17 carries a piston 18, which is connected thereto by bolts 19. The piston 18 extends downwardly from the yoke 17 and into a c linder 20 formed in the upper end portion 0 the connecting rod 7, a land nut 21 being connected to the outer en port1on of the connecting rod 7 and holding the packing 22 securely in osition to prevent leakage betwen the cylin er and piston 18.

The piston 18 is provided with a central bore 22 which registers with an opening 23 in the yoke 17 Extending through the openmg 23 and into the bore 22 is a plunger 24, having one or more weights 25. The cylinder 20 may be supplied with liquid, such as water, and in the operation of the press, when the connecting rod 7 is forced downwardly by the crank 4 and slide 5, it will be seen that this action takes place through'yokes 15 and 17 and the piston 18 exerts a force against the liquid in the cylinder 20. It will thus be seen that a yieldable connection is provided between the crank pin and plunger or pressure member 10 and when the force exerted by the crank pin 4 exceeds a predetermined maximum (this maximum being determined b the weights 25 carried by the plunger 24 the pressure exerted by the piston 18 in the cylinder 2O overcomes 25 and forces the plunger outwardly in the bore 22. In this manner, a definite pressure is obtained at each stroke of the plunger 10, regardless of whether a lesser or greater quantity of powder is supplied to the mold 11. In practice, the space between the end of the piston 18 and the bottom of the cylinder 2O permits sufiicient movement to take care of the variations caused by unequal feeding of the powdered material.

In operation, the crank pin 4 turns to its lowest point while the punch or plunger 10 is compressing the powdered material. Near the end of the stroke, the compression of the powdered material is complete, and, as the crank pin continues over dead center, it carthe resistance of the weights j ries the slide 5 with it, and, owing to, the

above described connections, forces'the piston 18 more deeply into the cylinder 20.

This action against the liquid in the cylinder, forcibly moves the plunger 24 outward: ly, and in this manner the crank pin has been permitted to descend in the final part. of its stroke without forcing the punch or pressure member 12 to further compression. As a matter of fact,.when the crank pin 4 passes over dead center and also slightly before and after this movement, the action of the punch 10 has been regulated by the amount of weight on the/plunger 24 acting v on the piston 18. This feature has been found to be of considerable importance as it permits a slight dwell of the punch 10 during the period of-maximum compression. This is of a particular advantage when using powders which are bulky, and as a consequence, require the elimination of a large quantity of air, because otherwise, the molded piece is apt to break open as soon as the pressure is relieved, due to the air which did not have time to escape,and became imprisoned in the molded piece.

In the alternate form of the invention shown in Fig. 4, the machine frame 27 is substantially E-shaped and is provided with a rotating table 28 having mold cavities 29 in which the material is compacted. The ejector punch 30 may be mechanically operated through links 31 and32 by a crank pin 33 on the driven wheel 34, which may be rotated by any suitable source of power.

The pressure punch 35 is vertically reciprocable in the machine frame and extensible into a cavity 29 in the table 28, an abutment 36 forming a shoe against which the punch 35 operates. It will be understood that an article is first compressed, and, during such compression, the punch 30 operates to eject a formed article at a point opposite from the point of compression.

For reciprocating the pressure punch 35, a toggle mechanism is provided which consists of links 37 and 38, the link 37 being pivotally connected to the punch 35 and the two links being pivotally connected together and to the crank pin 33 by a link 39, the link 38 being connected at its opposite end to a piston 40.

The piston 40 reciprocates in a cylinder 41, which is connected bya passage 42 to the accumulator cylinder 43, which is vertically disposed and in which is mounted the accumulator piston 44, which is provided with weights 45. Liquid is disposed in the passage 42, and it will be understood when sufficient pressure is exerted by the piston 40 against the liquid in the passage 42, the accumulator iston 44 will be elevated. From the above escription it is apparent that movement of the crank 33 operates the toggle through the connecting link 39, the punch 35 is forcibly pressed against the shoe 36, thereby causing the powdered material within the cavity 29 to be compressed. Smce one member of the toggle rests upon the hyformed will not be disrupted when pressurev is relieved.

While I have described my improved machine inmore or less detail to comply with the requirements of the statute it is nevertheless, desired that this detail description be considered merely as illustrative and not as limiting, and it is to be understood that changes and modifications may be made by those skilled in this art without departing from the invention as defined in the appended claims.

What I claim as new and desire to Letters Patent is:

1. A press comprising a reciprocatory plunger, 9. connecting rod pivoted to said plunger having a longitudinally elongate guide, a power crank, a slide operatively connected to said crank and movable in said guide, and a fluid pressure device connecting said connecting rod and slide for compensating for a counteracting force on said plunger in excess of a predetermined maximum.

2. A press comprising a reciprocatory plunger, a connecting rod pivoted at one end to said plunger, said rod having a longitudinally elongate guide, a power crank, a slide on said crank and movable along said guide, a cylinder on the outer end of said connecting rod, a plunger carried by said slide and movable in said cylinder, pressure fluid in said cylinder, and a weighted piston in said plunger adapted to be forced outwardly when the counteracting force of said plunger exceeds a predetermined maximum.

3. A press comprisingareciprocatory pressure member, a rod pivoted at one end to said member and having a. longitudinally elongate guide, a power crank, a slide, on said crank and movable in said guide, and means including a weighted member associated with said slide for holding said pressure member in compressing position during a portion of the outer travel of said crank in a direction away from the pressure member.

4. A press comprising a reciprocatory pressure member, a rod pivoted at one end to said member and having an elongate slot, a power crank, a slide on said crank and reciprocable in said elongate slot, a cylinder in the outer secureby end of said rod, pressure fluid in said cylinder,

a plunger in said cylinder, a connection between said plunger and slide, said plunger having passage extending therethrough, a piston in said passage, and removable weights on the outer end portion of said piston.

5. A press comprising a reciprocatory pressure member, a rod movably connected at one end to said member and having an elongate guide, a power crank, a slide on said crank.

operable along said guide, and a fluid pressure device including a weighted piston, vice being associated with said slide and rod for holding said pressure member in compressing relation during the interval in which the rod is swung from one side to the other by said crank. 6. A press comprising a reciprocatory pres sure member, a rod movably connected at one end to saidpressure member and having a longitudinally elongate slot, a power. crank, a slide on said crank reciprocable in said slot, a cylinder in the outer end of said rod, pressure fluid in said cylinder, a piston in said cylinder, a yoke connected to said piston, means connecting said yoke and slide, said said 'depiston having an opening extending there-.

'7. In a press, a reciprocatory plunger, driving means for reciprocating the plunger, a v

connection secured to the driving means and to the plunger for reciprocating the plunger from the driving means, a hydraulic device including a cylinder and a piston thereincarried by and forming a part of said connection and movable therewith to receive the thrusts from the driving means and to transmit same to said plunger, and means for exerting pressure on thefiuid independent of that exerted by the piston on the fluid for compensating for a counteracting-force on the'plunger vin excess of a predetermined maximum and to;

momentarily hold the plunger at the limit of its working stroke prior to its idling stroke.

In testimony whereof I have hereunto signed my name to this specification.

. RALPH SEABURY. 

